1. Field of the Invention
The present invention pertains to a low and weakly-interlaced industrial polyester multifliament yarn, which has excellent flatness and flat uniformity, and in which the number of monofilament layers is properly controlled according to a denier of the low and weakly-interlaced polyester multifilament yam and monofilaments are weakly interlaced, thereby reducing a surface brightness gradient of a coated fabrics, produced using the low and weakly-interlaced polyester multifilament yarn, when light is irradiated to the coated fabrics, and a method of producing the same. More particularly, the present invention relates to a low and weakly-interlaced polyester multifilament yarn, which is usefully applied to weave woven fabrics or to knit an industrial knitted fabrics with a relatively low density without a twisting or sizing process, and which is relatively thin and has excellent flatness, thereby being usefully applied to coated thin woven fabrics or knitted goods with a smooth surface, and a method for producing the same. In this regard, monofilaments constituting the coated fabrics occur when light is irradiated to the coated fabrics. On the other hand, when the average tear strength of the interlaced portions is less than 3 gf, the yarn is scarcely interlaced, and thus, the condensation of the yarn is reduced, thereby significantly reducing workability of an after-treatment process, such as a weaving process.
2. Description of the Prior Art
As well known to those skilled in the art, an air interlacing process includes blowing air to a multifilament yarn at a predetermined angle under a predetermined air pressure to collide air to the multifilament yarn, thereby bringing about a turbulence around the multifilament yarn. In this respect, the turbulence around the multifilament yarn causes the interlaced portions and the irregular entanglement of monofilaments constituting the multifilament yarn. The air interlacing process enables the multifilament yarn to be condensed without a conventional twisting or sizing process. Accordingly, the air interlacing process contributes to easily conducting weaving and knitting processes, and to improving the physical properties of end products, produced using the interlaced multifilament yarn. In this respect, the air interlacing process is advantageous in that because the conventional twisting or sizing process may be omitted the production costs are reduced and the workability is improved.
One example of the conventional air interlacing process is disclosed in U.S. Pat. Nos. 3,701,248 and 5,518,814, in which an interlaced multifilament yarn is strongly condensed so as to enable a section thereof to be conglomerated, thereby improving the weaving workability without a sizing and twisting process.
The conventional interlaced yarn, produced according to the conventional air interlacing process, has relatively many interlaced portions, that is, 5 or more per one meter as shown in FIG. 8. Additionally, the conventional interlaced yarn has different lengths of the interlaced portions (LK) and different thicknesses at different openings thereof, and thus, a surface of a coated fabrics, containing the conventional interlaced yarn, is non-uniform.
Furthermore, the conventional interlaced yarn, produced according to the conventional air interlacing process, is problematic in that lengths between the interlaced portions (LBK) are different from each other, its thickness uniformity is poor because thickness differences between the interlaced portions and openings are relatively large, the capillary or fluff easily occurs because relatively high air pressure is applied to the conventional interlaced yarn to reduce qualities of end products, and the production costs are increased.
As well, Korean Pat. Laid-Open Publication No. 2002-48368 recites a process of producing a low and weakly-interlaced yarn with a few interlaced portions by controlling air pressure of an air interlacing device, tension of the interlaced yarn, and a winding helix angle on a yarn package. However, this process is disadvantageous in that many strongly interlaced portions are formed in the interlaced yarn to bring about a brightness gradient on a surface of a coated fabrics acting as end products, produced using the interlaced yarn, when the coated fabrics is irradiated by light or light is transmitted through the surface of the coated fabrics. Hence, the interlaced yarn is not suitable as the coated fabrics for a banner advertisement.